Stringed musical instrument bridge with dual pickups



A. JOHNSON Nov. 10', 1970 STRINGED MUSICAL INSTRUMENT BRIDGE WITH DUAL PICKUPS v 2 Sheets-Sheet 1 Filed out. 10, 1968 INVENTOR. c/O/V/VSO/V BY v @flii Nov. 10,1970

A. JOHNSON STRINGED MUSICAL INSTRUMENT BRIDGE WITH DUAL PICKUPS Filed Oct. 10, 1968 2 Sheets-Sheet 2 Y! 7 7 ?Z l f 92 1/ I /I/ 4 /04 g m g INVENTOR. FQfD gM/KS'O/l/ United States Patent Ofice 3,539,700 STRINGED MUSICAL INSTRUMENT BRIDGE WITH DUAL PICKUPS Alfred Johnson, 147 Hamlin Road, Buffalo, N.Y. 14208 Filed Oct. 10, 1968, Ser. No. 766,521 Int. Cl. Gh 3/00; G10d 5/00 US. Cl. 841.16 6 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to improved and novel electrical bridge arrangements having a pickup for violins and other musical instruments of the violin family, and more particularly, the invention relates to a two-section electrical bridge having the upper section for modifying and changing the movement of the strings to an electrical impulse or signal, while the lower section changes or converts the vibrations of the body of the musical instrument to electrical signal impulses. Thus, when these composite signals are amplified both the frequency of the string movement and the timbre of the body of the musical instrument are amplified and an improved musical effect is achieved.

It is an object, therefore, of the present invention to provide a set of pickups in each of two sections of a bridge so that the resulting impulse signals derived therefrom can be used to amplify the sound of all string instruments, although it is pointed out that the bridge pickup arrangement is designed for the base violin and other members of the violin family.

An object of the present invention is to provide a magnetic and soft metal being magnetically responsive, such as soft iron, and the like, that is convenient in construction as well as rugged and will last indefinitely, as well as economical in manufacture.

Another object of the present invention, as well as a primary advantage thereof, is that the pickup in each of the sections is mounted over the sound post of the violin, and an improved musical effect is achieved from a standard or conventional type of violin instruments. In this installation of the bridge of the present invention, the bridge does not have to be anchored to the instrument, but it simply replaces the conventional bridge by loosening the strings as is done to replace the strings in replacing the conventional bridge, and it is found that the pickup characteristics will match the electrical impedance of most, if not all, base audio amplifiers. The pickup, therefore, is mounted over the sound post and picks up the vibrations of the back as well as the front of the musical body, as well as the vibrations of the strings, and thus produces essentially and substantially a true reproduction of the sounds of the instrument as would be possible.

The above and other objects and advantages of the invention will become apparent upon full consideration of the following detailed description and accompanying drawings in which:

FIG. 1 is a front elevational view of the electrical bridge element of the present invention;

FIG. 2 shows a similar view of the electrical bridge, but having a central portion thereof showing the upper section and the lower section end cross-section, so that the 3,539,700 Patented Nov. 10, 1970 details of the preferred embodiment of the inventiion are shown;

FIG. 3 is a cross-sectional view taken along a central axis of FIG. 2, and showing the manner in which the bridge supports the strings;

FIG. 4 shows a cross-sectional view taken along lines 4-4 of FIG. 2;

FIG. 5 shows a modification of the invention compared with that embodiment of FIG. 2, and also showing a concept of the invention;

FIG. 6 shows a cross-sectional view taken along lines 66 of FIGS; and

FIG. 7 shows a form of a rubber insulator and a mount for the coil shown in FIG. 5.

Referring now to the drawings there is shown a bridge adapted to be supported from a sound post of a violin type instrument 12. Also shown on the bridge 10 are mounting screws 14, 14 for securing a plate 16, and a plate 18, 18, respectively, also retained by screws 20, 20.

There is provided a knurled knob 22, 22 on each side of the bridge for changing from electrical to manual use of the bridge 10.

The design of the bridge is of thesame measurements generally as the conventional type of bridge, but there are different contours shown in the feet 24, 24 thereof. While FIG. 1 shows a rear view of the bridge with the coved 16, the carvings 28, 28 are observed fromboth sides as seen also in FIG. 2.

There is particularly shown in FIG. 4 a set of pins 30, 30 in the section 32 made of metal and which are permanently attached to the upper section 34 of the bridge. The pins 30, 30 are insulated from the lower section 36 with a rubber tubing 38 as seen in FIG. 2.

Lock or set screws 40 are used to prevent the upper section 34 from separating from the lower section 36 where a slot 42 provides the clearance so that the lock screw 40 does not touch the pin 30 during normal use of the bridge.

The upper section 34 is mounted on live rubber material 46, and it is allowed thereby free movement for making its action relevant to the armature 48 which is composed of a permanent magnet, or even a soft iron material, being held in place with a bracket and screw assembly 50 which provides an air gap between the pole piece and the armature 48.

A pickup 52 is seen insulated from the bridge with a live rubber material 54 and is made secure therein with a bracket member 56 and a screw 58. The pickup 52 is composed of a bracket 60 and a. magnet 62 having two coils 64, 64. The coils are wound on a pole piece 66 held in place with screws 70.

The coils 64, 64 are connected in electrical series relation with the leads terminating in the socket 68' which is retained in place by screws 70.

There is in FIG. 3 a side view showing the aramature 48 of the upper section 34 having a bracket and screw assembly 50. The knurled knobs '22, 22 are used to connect the upper pins 30 with lower pins 72 so that contact is made mechanically between the upper section 34 and the lower section 36 to restore full volume control for manual use of the bridge 10, which is somewhat muted generally due to insulation produced by tubing 38, 38. The pins 72, 72 are prevented from rotation by having a square shank portion 74 in a slot 78 which is recessed in a hole 80.

A threaded shank 82 should be of fine threads and provides a tight fit to the knurled knob 22 for preventing chatter or vibration as well as providing fine calibration during normal use of the bridge 10.

The bridge 10 may be made of any hard wood or other suitable plastic materials such as hard rubber and any of the well-known new plastics such as Teflon and the like.-

It should be emphasized that the armatures 64 may be made of soft magnetic iron material and this is in lieu of a permanent magnet if desired. This is found to provide better results, particularly where it is located on the lower half of the upper portion 34.

FIG. 5 shows a single coil 90 being used in lieu of two coils shown in FIG. 2. An air gap 92 is present between the coil 90 and the armature 94 on each side of the coil 90 as shown. The armature is composed of soft iron mounted in the upper section of the bridge 34 and the armature 94 in the lower half is shown in the lower portion of the bridge 36. The armature 94 in the upper bridge 34 may be insulated so as to reduce its sensitivity thus minimizing excess finger noises also due to drag.

Screws 96, 96 are provided for attaching the armatures 94 to both sections of the bridge, respectively. Pins 98, 98 hold the bridge sections 34, 36 together in the same manner as shown in FIG. 2, and rubber insulation material '98 is provided to mount the coil 90* as well as the spacing of the sections 34, 36.

FIG. 6 shows the end view of the bridge of FIG. 5 and in which the bridge is provided with end covers 100,100. A socket arrangement for attaching a cord to the amplifier (not shown) is also provided. The covers 100, 100 are retained in place by screws 102 mounted on the upper section 34 to allow free movement of the upper section without regard to the lower section of the bridge, and thus allow as well as provide for picking up timbre movements of the instrument. FIG. 7 shows a coil mount 104 and a permanent magnet 106, and there is adapted to be disposed between the covers 100 and the coil mount 104 a felt pad 110, 110 shown in FIG. 6.

It is seen by the construction and arrangement of these operable parts of the embodiments of the invention as shown described and set forth herein, that the objects and advantages of the present invention are presently achieved.

Additional embodiments of the invention in this specification will occur to others and, therefore, it is intended that the scope of the invention be limited only by the appended claims and not by the embodiments described hereinabove. Accordingly, reference should be made to the following claims in determining the full scope of the invention.

What is claimed is:

1. An electrical bridge pickup arrangement for musical instruments such as violins and the like comprising a bridge consisting of an upper and a lower portion, said lower portion adapted to rest upon a sound post of a violin, and said upper portion supporting strings of said violin,

pins mounted in the upper portion extending into the lower portion in telescopic relation, said upper and lower portions separated by an elastomeric material,

a pickup armature in said upper portion focused to pick up vibration of said strings,

and a pickup armature in said lower portion focused to pick up vibrations of said sound post.

2. The invention of claim 1 wherein the supporting feet of the lower portion are contoured to concavely pick up sound of said sound post for focusing the sound to said armature of said lower portion.

3. The invention of claim 2 wherein focusing apertures are radially disposed in the upper portion to assist focusing therein.

4. The invention of claim 3 wherein lock means are provided in the lower portion to engage the telescopically engaging pins.

5. The invention of claim 4 wherein said armature is of permanent magnet material.

6. The invention of claim 4 wherein said armature is of soft iron.

References Cited UNITED STATES PATENTS 7/1936 Pfeil 84--1.15 6/1965 Rizzutti 841.16 

